21243524521 has 8 divisors (see below), whose sum is σ = 21402441344. Its totient is φ = 21085157520.

The previous prime is 21243524509. The next prime is 21243524527. The reversal of 21243524521 is 12542534212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21243524521 - 2¹⁷ = 21243393449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21243524527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 59730 + ... + 214603.

It is an arithmetic number, because the mean of its divisors is an integer number (2675305168).

Almost surely, 2^21243524521 is an apocalyptic number.

It is an amenable number.

21243524521 is a deficient number, since it is larger than the sum of its proper divisors (158916823).

21243524521 is a wasteful number, since it uses less digits than its factorization.

21243524521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 274911.

The product of its digits is 19200, while the sum is 31.

The spelling of 21243524521 in words is "twenty-one billion, two hundred forty-three million, five hundred twenty-four thousand, five hundred twenty-one".